* {
  margin: 0;
  padding: 0;
}

/* 大背景 */
/* 默认状态html和body的高度是0,导致cover缩放背景图不生效 */
html {
  height: 100%;
}
body {
  height: 100%;
  background: url('../images/f1_1.jpg') no-repeat center 0 / cover;
  /* background-size: cover; */
}

/* 云彩 */
.cloud img {
  position: absolute;
  left: 50%;
}
.cloud img:nth-child(1) {
  margin-left: -250px;
  top: 20px;
  animation: cloud 1s linear infinite alternate;
}
.cloud img:nth-child(2) {
  margin-left: 400px;
  top: 100px;
  animation: cloud 1s linear infinite alternate 0.4s;
}
.cloud img:nth-child(3) {
  margin-left: -550px;
  top: 200px;
  animation: cloud 1s linear infinite alternate 0.6s;
}
@keyframes cloud {
  100% {
    transform: translate(20px);
  }
}

/* 文字 */
.text {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  animation: text 1s;
}
/* 文字动画 */
@keyframes text {
  0% {
    transform: translate(-50%, -50%) scale(1);
  }
  20% {
    transform: translate(-50%, -50%) scale(0.1);
  }
  40% {
    transform: translate(-50%, -50%) scale(1.4);
  }
  70% {
    transform: translate(-50%, -50%) scale(0.8);
  }
  100% {
    transform: translate(-50%, -50%) scale(1);
  }
}